The Revolutionary Dialysis Container specifically relates to dialysis of biological samples in biochemical and immunochemical studies.
In biochemical processes such as extraction, purification, conjugation and characterization, excess reagents are removed from desired molecules by dialysis. To perform dialysis a sample is taken in a bag with semipermeable membrane and stirred against buffer present in a large container. With time large molecules are retained inside the bag while small reagent molecules go out into buffer surrounding the bag. During dialysis, buffer is changed several times so that undesired molecules along with buffer are removed. Routinely, glass or plastic beakers are used to hold buffer. The first problem with these oversized containers is lack of proper grip. A slip causes loss of valuable sample, spill of reagents and breakage of the container. The second problem is in mixing buffer. Theoretically, fast mixing results in quick exchange of chemicals across the membrane. But, in practice, when buffer is mixed, a vortex develops and makes dialysis bag dive to bottom where either the bag pushes magnet go out of spin or magnet damages the membrane of bag. Also, some samples due to the presence of high amount of salt automatically sink to bottom and face similar consequences. These events not only impair dialysis but also result in total or partial loss of valuable sample. The third problem is in exchange of used buffer with fresh. Ordinarily, used buffer is poured out from the wide mouth of beaker. Dialysis bag and spin magnet often slip into sink and get contaminated with undesirable chemicals and materials. In other instances when samples contain radioactivity, therapeutic drugs or toxins, it is undesirable to touch or contaminate other surfaces. Therefore, there is a need for a better dialysis container.
Shibora in U.S. Pat. No. 5,141,327 describes a stirrer that includes a stator and a housing containing a rotor. The rotor is a hollow cylinder with openings at both ends and with slots in the center. The liquid which flows in through two communication ports of housing is sucked into the rotating rotor, mixed and returned through slots of rotor to the container through an additional port present in the center at the top of housing. This configuration has no mechanism to prevent dialysis bags of different diameters and lengths either blocking the ports or getting sucked into housing and then, into the rotating cylindrical rotor. Therefore, the dialysis bags may block the flow of liquid, may get ruptured by the rotor or may stop the motion of rotor itself. The unit is bulky and needs maintenance.
Hyden in U.S. Pat. No. 4,192,748 describes a dialysis apparatus where a long dialysis membrane forms a partition between a sample to be dialyzed and the buffer to be used in dialysis. This apparatus which has several peripheral equipment, is expensive, bulky, and requires extensive maintenance. It is highly suitable for patient care. For instance, blood is continuously pumped into apparatus to remove unwanted chemicals and the dialyzed blood is then returned to the body of patient.
Shukla in U.S. Pat. No. 5,733,442 describes a microdialysis system for the dialysis of microliter volume of biological materials. However, this system is not convenient for samples of higher volumes (several milliliters to deciliters). Placing a small magnet inside the chamber is cumbersome and inefficient for rapid stirring. Also, the magnet does not stir outside buffer surrounding the dialysis system. Besides, the area of membrane, and therefore the volume of sample, exposed for dialysis is small when compared to the area of an entire bag exposed to buffer. Hence, the microdialysis system takes a lot longer time to complete dialysis of samples.